1. Field of the Invention
The present invention relates to a two-dimensional adjusting structure, in particular, to a two-dimensional adjusting structure for a projection apparatus.
2. Descriptions of the Related Art
As digital data becomes increasingly popular, the use of projection apparatuses for presenting digital data also increases accordingly in many conditions and places. Generally, the position of projection image has to be adjusted before using a projection apparatus so that the projection image can be displayed on a projection screen entirely and clearly.
Conventionally, for a non-fixed projection apparatus, the adjustment in position of the projection image requires manual adjustment in the horizontal position of the image. Meanwhile, by operatively associating with a support rack attached to the projection apparatus, the vertical height of the image is adjusted. Moreover, in case the support rack has an insufficient length, the projection apparatus would need to also be raised to match the height of the projection screen and project the image. Such a complex adjustment process becomes inconvenient when using the projection apparatus, and inappropriate adjustments often leads to deflected projected images. On the other hand, for a fixed projection apparatus, the adjustment in position of the projection image has to be done in advance when the projection apparatus is installed so that the projection image matches with the screen. In the latter case, when the projection apparatus is to be used in a given space, the relative position of the projection apparatus and the screen must be pre-considered. Once the projection apparatus is installed, it will be very difficult to adjust the projection image, which causes additional limitation when using the projection apparatus.
To overcome the inconveniences in adjustment of the projection apparatuses described above, a conventional method for adjusting the position of a projection image has been proposed. As shown in FIG. 1, a lens 10 is mounted to a two-dimensional adjusting structure 1 disposed in a projection apparatus. The two-dimensional adjusting structure 1 comprises four bases 11a, 11b, 13a and 13b. The base 13a is adapted to move along a first axis X with respect to the base 13b, the base 11a is adapted to move along a second axis Y with respect to the base 11b, and the base 11a is further connected with the base 13b. In this way, the lens 10 can be adjusted in position. The principle of this adjustment method is to use a combination of two independent one-dimensional adjusting platform assemblies that result in the relative movement along two axes X, Y respectively. Consequently, the adjusting structure has a bulky volume and a heavy weight, and the material cost thereof also increases with the complexity of the elements. Such a bulky adjusting structure can only be used in large projection apparatuses. For typical portable projection apparatuses with a small volume and a limited internal space, it is inappropriate to install such an adjusting structure, which degrades the applicability of the adjusting structure.
Accordingly, efforts still have to be made in the art to provide a two-dimensional adjusting structure which has a small volume and a light weight. Thereby, the two-dimensional adjusting structure can be applied more widely to various projection apparatuses to perform two-dimensional position adjustments in the lenses of the projection apparatuses relative to the screen in a simple way, thereby presenting a complete and clear projection image at the correct position on the screen.